Lifting jack



; --July 2, 1929. 4 v; K. HOTT LIFTING JACK Filed Sept. 18, 1924 3 Sheets-Sheet l INVENTOR.

ATTORNEY July 2, 1929.

l. v. K. HOTT LIFI'ING JACK Filed Sept. 18, 1924 5 Sheets+$heet 2 INVENTOR; J a/I K/ f/av-r ATTORNEY.

July 2; 1929.,

|. v. HOTT LIFTING JACK Filed Sept. 18, 1924 a Sheets-Sheet- 1 iwo INVENTOR. 13w KA. A a 77" ATTORNEY Patented July 2, 1929.

UNITED STATES PATENT OFFICE."

ION V. K. HOTT, 0F DAYTON, OHIO, ASSIGNOR TO THE JOYCE-CRIDLAND COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

mr'rmo JACK.

Application filed September 18, 1924. Serial No. 738,556.

This invention relates to lifting jacks and one object of the invention is to provide a jack which will have a high lift in proportion to its height in its lowered position.

A further object of the invention is to provide a jack in which the lifting element will flex or fold upon itself when in its lowered position, but will be rigid in its extended position. p a

A further object of this invention is to provide a jack of this kind which will'be simple in construction, positive in operation and inexpensive to manufacture. i

Further objects of the invention will appear as the device-is described in detail.

In the accompanying drawings, Fig.- 1 1s a front elevation of a jack embodying my in-- vention; Fig.2 is a top plan of the same;- Fig. 3 is asidev elevation of the same; Fig. l

is a sectional View taken on the line {1i of Fig. 2; Fig. .5 is a detail view of a portion of the lifting element; Fig. 6 is a transverse sectional view taken on line 66 of Fig. 4, andFig. 7 is a transverse section takenin the lines 7-7 of Fig. 5. r

In these drawings I have illustrated one embodiment of my invention, but it will be understood that this particular embodiment has been chosen forthe purpose of illustration only and that the invention may take various forms and may be embodied in jacks or similar devices of various kinds without departing fromthe spirit thereofj In the form of the invention here shown the jack comprises a base 1 which has mounted thereon, and preferably formed integral therewith, ahollow standard or housing 2, the upper portion of which is of reduced diameter, as shown at 3, and is connected with the lower portion by means of inclined walls 4. This standard or housing constitutes the supporting structure for the lifting element which is slidably mounted in the reduced upper portion of the housing which forms a guideway therefor. Y

The lifting element is preferably of such a character that it will be normally flexible and can be flexed or folded upon itself in the housing2, so that an element of relatively great length can be folded into'a housing of comparatively small height. This flexible lifting element is of such a character that when it is moved to its extended position it will lose its flexibility and will form a rigid lifting element to support the load. Preferably the lifting element consists of two members, each of which is normally flexible and:

one or both of which are provided with parts adapted to be moved into engagement with parts of theother member when thelifting element as a whole is moved to its extended position and to so connect the two member s that neither of them can be flexed, thus rendering the lifting element, or that portion of the same whichhas been moved to its extended position, rigid. In the present'construction, each member of the lifting element comprises a series'of linkswhich are pivotally" connected one to theother, after the manner of a chain.

As here shown, the lifting element consists of two flexible members5 and 6, portions of" which lie in the g'uideway 3 of the housing and. the upper ends of which are pivotally connected with the load-engaging member 7. Each member of the lifting element consists of a series of links and each link is provided with a projection which extends laterally to ward the other member of the lifting element,

and the projections of the links of the two members are of such character and are so ar-. .ranged that. theywill be moved into'interlocking engagement. as the links enter the guideway 3 during the upward movement of the lifting element. The links may be of any suitable character and the projections may be formed thereon 'in any suitable manner. Preferably each link consists of a. series of plates 9 arranged side by side and'connected one lor'the other by. means of .pivot pins 10, which also serve to pivotally connect'the ad jacent links'one to the other. In the present construction each link. comprises. four plates and these plates are arranged in pairs at the opposite sidesof thelink. The pivot pins 10 have enlarged intermediate portions 11, which serve to space the innermost links apart, and theouter ends of the pivot pins are upset or riveted to retain the plates thereon. The plates ofcorresponding pairs of adjacent linksare arranged alternately on the same pivot pin. Each plate 9 of each pair is provided with a laterally extending projeotion 12, which is preferably T-shaped and has its upper and lower ends beveled after the manner of a gear tooth. The plates of adjacent links being arranged alternately on the connecting pin 10 it will be apparent that 2 is here shown as having a central partition 13 provided at its upper end with a tapered or inverted V-shaped head 14. "When the lifting element is in its lower-most position, the lower portions of the two members thereof will lie within the two compartments formed on the respective sides of the partition 13. When the lifting element is elevated the two members will be drawn through the respectivepassage-ways formed between the tapered head 14 and the two inclined walls 1 of the housing and will pass from these passageways into the guideway 3. The arrangement of the passage-ways is such that the flexible members in passing through the same into the guideway 3 will cause the links to be tilted to such ositions as to 0 en the s aces between the corresponding projections on the alternate links thereofand to cause the upper end or tooth of the projection on one member to enter thespace between corresponding projections on the other member, and as the lifting element continues its movement to cause a succeeding projection on said other member to engage in the rear of the lower tooth of the projection on the first mentioned member. Thus when the two members have assumed their parallel positions each projection of each member will be firmly locked between those projections of the other member with which it is in engagement. It will be apparcnt therefore that when the lifting element is extended above the housing the several links of each member thereof will each have its projections interlocked with projections-carried by the other member, and as a result the several links of both members are rigidly held against movement about their pivotal connections one to the other and the lifting element as a whole becomes rigid and forms a very firm support for the load.

The lifting element may be actuated in any suitable mannerv and power may be applied either to one or to both members thereof. In the present instance, I have applied power to one member only of the lifting element and have provided for this purpose a sprocket wheel 15 mounted on a shaft 16 journaled in bearings in the enlarged portion 17 formed above one of the inclined walls 4 of the housing. Theteeth of this sprocket wheel enter the spaces between the pivot pins of one of the flexible members in the same manner in which a sprocket wheel engages a sprocket chain and thus causes the. lifting element as a whole to be moved lengthwise. Power may be applied to the sprocket wheel by any suitable mechanism. As here shown, the shaft 16 has secured thereto a worm wheel 18 which meshes with a worm 19 carried by shaft 20 and, in the present instance, is provided with detachable crank or handle 21. The worm and worm wheel are of low pitch so that the Worm wheel will not rotate the worm and consequently these parts form a lock which firmly holds the lifting element in its adjusted positions. hen it is desired to lower the lifting element, the worm 19 is rotated in a reverse direction, thus rotating the sprocket wheel in a reverse direction and either permitting the lifting element to move downwardly under the weight of the load or causing the lifting element to be driven down by the action of the sprocket wheel.

The operation of the mechanism will be readily understood from the foregoing descripti on and to be apparent that I have provided a lifting jack which is very simple in its construction and operation and'which may have a very high lift in proportion to the height of the housing. nism is of a strong durable character and the lifting element is rigid and firm when in its extended position. I believe myself to be the first to have provided a lifting jack or similar device in which the extendible element is normally flexible and is rendered rigid when it is moved to its extended position and therefore, while I have shown and described one particular embodiment of my invention I wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a device of the character described, a supporting structure, a lifting element carried by said supporting structure and comprising two members each of which is normally flexible in both directions from a straight line position, said members being arranged to cooperate in their extended positions to prevent either member from being flexed, and means for actuating said lifting element.

2. In a device of the character described, a supporting structure, a lifting element carried by said supporting structure, and comprising two members each of which is normally flexible in both directions from a straight line position, oneof said members having parts arranged to be moved into engagementwith the other member as said lifting element is moved to its extended position and to connect said members one to the Further the mechaother to prevent the same from being flexed, and means for actuating said lifting element and moving said parts into operative engagement with said other member.

3. In a. device of the character described, asupporting structure, a lifting element carried by said supporting structure and comprising two members, each of which is normally flexible in both directions from a straight line position, said members having cooperating projections arranged to be moved into interlocking position to prevent both members from being flexed, and means for actuating said lifting element and causing said cooperating projections to be moved into interlocking positions.

4. In a device of the character described, an extensible element comprising two members each of which is normally flexible in both directions from a straight line position, said members having coo rating parts so arranged that said parts 0 one member will be moved into interlocking engagement with the corresponding par-ts of the other member when said element is moved to anextended position and will prevent said element from. being flexed while it is: in an extended position.

5. In a device of the character described, an extensible element comprising two members each comprising a plurality of links pivotally connected one to the other for movement about their axes in both directions from a straight line position, the links of the two members being provided with projections so arranged that-the projection on a link of one member will be moved into interlocking engagement with the corresponding projections on two links of the other member by the movement of said element into its extended posi tion and will prevent said element from being flexed while it is in an extended position.

In testimony whereof, I'aflix my signature hereto.

ION v. K. HOTT. 

